Depending on his performance in the Swiss stage race, Henao could become a key rider in Team Sky's line-up for the Tour de France.

Henao was suspended from the Team Sky's racing programme after the Tour of Oman in February. A monthly team review highlighted anomalous values in Henao's blood data. The team decided to send Henao back to his home country of Colombia to run tests to see what effects living at altitude had on the body. He returned to Europe in late May and underwent further testing at non-altitude levels.

Team Sky has revealed that the research programme was conducted by a team from the University of Sheffield with the cooperation of the Colombian anti-doping authorities. It started in Europe, continued for 6-weeks at altitude in Colombia and finished last week with final base-level tests in Nice. Team Sky said the findings have been given to WADA, the UCI and CADF and all urine tests are in the rider’s Biological Passport. The experts will also seek to publish a full scientific research paper in the coming months.

“By taking this structured, scientific approach, we’ve gained a better understanding of his readings and specific physiology and valuable insights into the effects of altitude," Team Sky manager Dave Brailsford said in a statement.

“We’re very pleased to welcome Sergio back to racing and are looking forward to having him at the Tour de Suisse. Our approach has been fair to both the rider and the team, and whilst it was our decision to take him out of racing, it is also ours that he returns with our full backing. He’s done everything that’s been asked of him, kept his focus and fully deserves to be racing.”

Henao is listed as a reserve on the official Tour de Suisse entry list, alongside Bradley Wiggins, Edvald Boasson Hagen and Kanstantin Siutsou. This means Team Sky can include any of the riders when the final start list is decided the afternoon before the race. Italy's Dario Cataldo, Joe Dombrowski and Philip Deignan are listed in the team for the nine-day race.

French newspaper L'Equipe suggested that Henao could be a leader for Team Sky at the mountainous Tour de Suisse because Wiggins has put on weight as he prepares to ride on the track for England at the Commonwealth Games in July instead of riding the Tour de France.

The Tour de Suisse begins on Saturday with a 9.4km time trial in Bellinzona.